You initially had the video-nvidia-470xx installed and working fine. With the update, came a newer version of the 470xx nvidia drivers
So, prior to 470.161.03 nvidia driver family, there was 470.141.03 version, and that was working fine for you. After update you noticed a decrees in performance. Then you switched to video-nvidia = that is the latest family with the version 525.60.11 that i know for sure has multiple regressions in performance, vaapi mentioned here Issue after upgrading to 525 series drivers · Issue #126 · elFarto/nvidia-vaapi-driver · GitHub and also discussed on cuEGLStreamProducerConnect returns error 801 on 525.53 driver - #7 by elFarto - Linux - NVIDIA Developer Forums
and i doubt somehow that for some GPU models this issue got fixed
Somehow i was actually hoping that by mentioning all the above you will disprove my initial concerns, and you actually did, because i didn’t much say what you can do, but what to look for, and now, as conclusion - it seems that also the latest legacy drivers introduced regressions and we should go back to 470.141.03 driver version from the 470xx family, to regain the performance we used to have.